<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
    *{margin: 0;padding: 0}
      .header{
          background-color:pink;
          color: aliceblue;
          
          /* 行高可以将一段文本撑开，让文字在行高中居中 */
          line-height: 80px;

          /* text-align设置文本对齐的方式
          center|left|right */
          text-align: center;




       }
    
    
    </style>
</head>
<body>
    <div class="header">
        hello world
    </div>
</body>
</html>